Bug 25045: Allow restricting anonymous requests on the public API

Bug 25045: Allow restricting anonymous requests on the public API

This patch introduces a check on the authenticate_api_request method for
the RESTPublicAnonymousRequests system preference. If disabled,
anonymous  requests get rejected.

The idea is to replicate the homologous OpacPublic system preference
behaviour.

To test:
1. Apply the Unit tests patch
2. Run:
   $ kshell
  k$ prove t/db_dependent/api/v1/auth_authenticate_api_request.t
=> FAIL: Tests fail, 200 is answered instead of 401 on the route.
3. Apply this patch
4. Repeat 2.
=> SUCCESS: Tests pass!
5. Sign off :-D

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>